Electron discharge device



SePL 3 1945. I Gf R. KILGORE: ETAL 2,407,163

ELECTRON DISCRGE DEVICE 2 Sheets-'Sheet 1 rnvlnillllllllllil l.

INVENTORS GEORGE' R. KILGQRE LUHRREN Edreams 8f m. SHULMHN. B ATTQRNEY SPt` `3 194@ G. R. KILGOREy ET Al. 2,407,163

ELECTRON DISCHARGE' DEVICE l .Filed July 28, '194s 2 sheets-sheet 2 z v il t i 6l 9 4i: y

ffl [510 Z5 il fa 1 E a J4 f if I l '5 Mining?"f Patented Sept. 3, 1946 UNITED STATES PATENT OFFICE ELECTRON DISCHARGE DEVICE i George Ross Kilgore, Princeton, Warren R. Ferris, Kingston, and Carl Shulman, Princeton, N. J assignors to Radio Corporation of America, a

corporation of Delaware Application July 28, 1943, Serial No. 496,420

voltages are applied to the deflecting electrodes to cause the electron beam to be periodically deflected across the aperture, to thus control the instantaneous flow of electron current to the collector, which may be used as an output electrode. sensitivity drops off as Athe frequency at which the tube is-operated is increased due to electron transit time effects. Efforts have been made to increase the deflection sensitivity or the transconductance of the beain deflection tube at ultra high frequencies, but such efforts have not met with a great deal of success. are also subject to limitation when operated at ultra high frequencies since the input circuit tends to be of low resonant impedance, resulting in an excessive amount of power being required to drive the tube. This decreases the effective power gain of the tube when operated as an amplifier. impedance include, among other things, radiation and resistance losses due to high circulating current in electrodes and leads.

I-n a copending application, Serial No. 445,118 filed May 20, 1942, in the name of Carl I. Shulman and George Ross Kilgore and assigned to the same assignee as the present application, a form of electron discharge device is disclosed which overcomes the objections pointed out above. In the apparatus there disclosed the beam deflection portion of the mount structure is so constructed that it subjects the electron beam to multiple successive additive deiiection, the beam being passed through a deflection system including a plurality of successive pairs of deecting electrode elements mounted within a hollow waveguide or cavity resonator.

The principal object of the present invention is to still further improve an electron dischargeV device of the beam deflection type.

Another object of our invention is to provide a device of the kind described, which is of small size andv completely shielded by a metal envelope.

A further object of our invention is to provide an electron discharge device of the multiple deflection type utilizing a tunable cavity resonator.

In such types of tubes, the deflection Tubes of this kind Fundamental causes of low resonantv 8 Claims. (Cl. 315-6) A still further object of our invention is to provide 'such a device in which the cavity resonator can be tuned externally of the metal en- A velope of the device.

The novel features which we believe to be characteristic of our invention are set forth with particular-ity in the appended claims, but the invention itself will best be understood by reference to the following description taken in ccnnectionf with the accompanying drawing in which Figure 1 is a longitudinal section of an electron discharge device made according to our invention, Figure 2 is a longitudinal section taken at with respect to Figure 1, Fig-ure 3 is a View of the beam forming system within the envelope as viewed in the direction of the arrow shown in Figure 1 and showing details of construction, Figure `l isa .transverse section taken along the line 4--4 of `Figure 2, Figure 5 is a schematic longitudinal section of the device shown in Figures 1 and 2 with its associated circuit elements.

In accordance with our invention the electron discharge device employs a metallic envelope and header `of conventional design within which the electrode system is mounted. Specifically and referring to Figures 1, 2 and 3, it includes the evacuated envelope I0 sealed by the usual header I I and insulating base I2 provided with the usual pins l2 and support leads sealed through the header.

The amount assembly is positioned vertically within the envelope so that the beam of electrons is directed downwardly toward the base. Mounted at the upper end of the envelope is the cathode assembly comprising indirectly heated cathode I4 partially surrounded by the beam forming and shielding electrode l5, these two electrodes being supported between the oppositely disposed insulating spacers I6 and Il, preferably of mica. The cathode I4 is provided with a lead I8 coated with insulating material I 9 as shown. Positioned at the other end of the mount assembly is collector 20 suitably supported from the header, for example, by means of support rod and bead construction i'' and provided with a lead 2U, through the header II.

Positioned between the cathode assembly and the collector is the beam forming electrode assembly and deflection electrode assembly. This comprises a preferably cylindrical member 2l having three spaced partition elements 22, 23 and 24, which; are provided with the aligned aper- 3 rod-like electrodes 25 and 21 between which the beam is directed and which control the direction of the beam n its further passage through the mount assembly. These beam directing electrodes are supported between the partition members by the bead and support wire assembly 28 and 2s, mica shields 35 and 3| being provided at opposite ends of the assembly. Leads such as 32 may be provided for the beam forming electrode assembly for applying a potential thereto.

At he lower end of the beam forming assembly is a beam deflection electrode assembly comprising the box-like hollow resonator 35 having the aperture 36, axially of which is positioned the rod 3'.' for providing a double aperture, a suppressor electrode 38 being positioned between the end of the cavity resonator 35 and collector 2S. The deilecting electrode elements include the block-like elements 39 and 43 provided with oppositely disposed teeth 39 and 40 which are spaced from center-to-center a distance equal to the distance travelled by an electron during a full period at the resonant frequency of the resonator 35 so that the deected electrons will come under the influence of the deflecting electrodes at each period so that deflection is always in the same direction.

The interior of the resonator is coupled to a waveguide by means of the coaxial line comprising outer conductor 45 and inner conductor 46, the end of the inner conductor extending within the waveguide il and supported in insulated spaced relationship with the glass insulator members d8 and 49, the inner end of the inner conductor being provided with coupling loop i! extending within the resonator. The resonator operates in such a mode that all teeth, for example SS', on one side of the resonator and forming deflecting electrode elements are at the same potential but 180 out of phase with the potential on the opposing deilecting electrode elements, for example 69.

For tuning purposes we provide a ring-like member ci?, shown in greater detail in Figure 4,

closely engaging the interior of the envelope of the tube. This ring is maintained under compression so that its tendency is to move outwardly toward the inner surface of the shell i0. Connected between it and the sides of the cavity resonator 35 are the arms 6l and 6i' which cause flexing of the sides of the resonator and hence a change in its resonant frequency upon compression of the ring 6E. Compression is accomplished, deforming the outside of the tube, by means of the arrangement shown by which cross bars 813 and 63 engage opposite sides of the shell il) adjacent to arms 5l and 6I. One end of the bars 52 and 63 are secured together by means of the rod 64, the other ends of the bars 62 and 63 may be brought closer together by means of screw ai 55 operated by means of the knob 66.

As shown in Figure 5, the cathode is maintained at a slightly positive potential with respect to the electrode shield l5 by means of conductors 49 and 9 connected to the voltage source 48 and the ground. The beam forming and deilecting electrode system is maintained at a high positive potential with respect to the cathode by means of the lead 55 connected to the high side of the voltage source 48. The suppressor 38 is connected to ground by means of conductor 5I. The collector may serve as an output electrode and is connected to the output transformer 53 by means of conductor 52 and maintained at a slightly lower potential than the beam forming and beam dellecting electrode system by means of the conductor 54. To vary the relative potentials between the beam directing rod electrodes 26 and 21, we provide a potentiometer arrangement 56 comprising a resistor 56' and voltage source 56", the voltage being fed to the deflection rods by leads 51 and 58. If desired a local oscillator voltage may be applied to the rods 2G and 21 by means of the oscillator 59.

In operation energy is fed into the cavity resonator by being directed down the waveguide lll and through the coaxial lines d5 and i5 to the loop at the end of the coaxial line. This energizes the cavity resonator so that as the beam of electrons is directed through the beam forming electrode system and between the deflecting electrode elements it will be deflected across the double apertures 36 of the cavity resonator and collected by means of the output electrode 20 which feeds the energy to the output transformer 53. As pointed out above, the spacing between the centers of the deilecting electrode elements is equal to the distance travelled by an electron during a full period of the applied voltage to the cavity resonator, so that the electrons will be deflected in the same direction by each pair of deflecting elements between which the electron passes.

Thus in accordance with our invention, we provide an electron discharge device of the beam deflection type, particularly suited for use at ultra high frequencies, which is of small size and which is completely shielded and in which the cavity resonator may be tuned externally of the envelope of the tube. By using the conventional header construction, sealing can be taken care of in a simple manner and assembly and pro'- duction facilitated.

While we have indicated the preferred embodiments of our invention of which we are now aware and have also indicated only one specific application for which our invention may be employed, it will be apparent that our invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used the purpose for which it is employed without departing from the scope of our invention as set forth in the appended claims.

What we claim as new is:

1. An electron discharge device including. an envelope, a cathode within said envelope for supplying a beam of electrons, moans within said envelope for receiving said electrons, and means positioned between said' cathode and receiving means and through which the beam path lies, and including a cavity resonator within said envelope, tuning means for said resonator connecting the cavity resonator' to the inner walls ofthe envelope and including a deformable ring contacting the inner walls of said envelope, and arms extending between said deformable ring and the walls of said resonator.

2. An electron discharge device including an envelope, a cathode within said envelope for supplying a beam of electrons, means within said envelope for receiving said electrons, and means positioned between said cathode and receiving means and through which the beam path lies and including a cavity resonator within said envelope, and means connecting the inner walls ofthe envelope to the cavity resonator including a split ring contacting the inner walls of said envelope, and arms extending between said split ring and the walls of saidv resonator, and

adjusting means positioned externally of the enveloper including a vise-like clamp for compressing the walls of said resonator adjacent the ends of said arms connected to said split ring for tuning said cavity resonator.

3. An electron discharge device including a metallic envelope, a cathode Within said envelope for supplying a beam of electrons, means within said envelope for receiving said electrons, and means positioned between said cathode and receiving means through which the beam path lies for periodically deiiecting the beam of electrons during operation of said electron discharge device, the delecting means includingr a cavity resonator and arms contacting the inner walls of said envelope and connected to the cavity resonator, andadjustable means positioned externally of said envelope and contacting the outer walls of said envelope for tuning the cavity resonator through said arms by Vpressure on the outer walls of the envelope.`

4. An electron discharge device including a metallic envelope, a cathode within said envelope for supplying a beam of electrons, means within said envelope for receiving said electrons, and means positioned betweenthe cathode and receiving means and throughgwhich the beam pathV lies, and including a cavity resonator within said envelope, tuning means for said cavity resonator connecting the cavity resonator to the inner walls of the envelope and including a split ring contacting the inner walls of said envelope, and arms extending between the split ring and the walls of said resonator, and adjusting means for compressing the envelope for contracting the split ring. Y

5. An electron discharge device including a metallic envelope, a cathode within said envelope for supplying a beam of electrons, means within said envelope forl receiving said electrons, derlecting means positioned between said cathode and receiving means and' through which the beam path lies for periodically deilecting said beam of electrons during operation of said electron discharge device, the deilecting means including a cavity resonator within said envelope,

the interior of said resonator being providedj with a plurality of opposed successively positioned deecting elements between which the beam path lies and tuning means for said resonator connecting the cavity resonator to the' inner walls of the envelope and `including a deformable ring contacting the inner walls of said envelope, and means connecting said deformable ring to walls of said resonator.

6. An electron discharge device including a metallic envelope, a cathode within said envelope for supplying a beam of electrons, means within said envelope for receiving said electrons, and deecting means positioned between said cathode and receiving means` and through which said beam path lies for periodically deecting said beam of electrons during operation of said electron discharge device, said deflecting means including a cavity resonator Within said envelope, said cavity resonator having a plurality of suc- 6 cessively positioned opposed deflecting elements spaced along the walls thereof and between which the beam path lies, said elements being spaced along the beam path equal to the distance travelled by an electron during a period of applied alternating voltage to said resonator, means connecting the inner walls of the envelope to the cavity resonator for varying the position of the walls of said resonator with respect to each other for tuning said resonator, and adjusting means positioned externally of the tube envelope for compressing the walls of said envelope to tune said resonator.

'7. An electron discharge device having an elongated metallic envelope, a header on said envelope closing said envelope and having a plurality of leads sealed therethrough, a cathode at one end of said envelope for supplying a beam of electrons; a collector within said envelope for receiving said electrons and a beam forming and deecting electrode assembly positioned between said cathode and said collector and including a beam forming ,means comprising a plurality of successively positioned apertured electrodes through which the beam path lies and a, cavity resonator within said envelope positioned between said collector and said beam forming assembly and including a plurality of oppositely disposed successively positioned deflecting elements positionedwithin the resonator, the beam path lying between said deflecting elements, said leads being connected to said cathode, collector and beam forming and deecting electrode assembly, a coupling loop within said resonator and a coaxial transmission line connected to said loop and said resonator for exciting said resonator when an alternating voltage is fed into said coaxial transmission line, said coaxial transmission line extending through said header and sealed thereto.

8. An electron discharge device having an elongated metallic envelope, a header on said envelope for closing said envelope and having a plurality of leads sealed therethrough, a cathode at one end of said envelope for supplying a beam of electrons, a collector within said envelope for receiving said electrons, and a beam forming and deiiecting electrode assembly positioned between said cathode and said collector and including a beam forming means comprising an apertured element through which the beam path lies, and

a cavity resonator within said envelope positioned between said collector and said beam forming means, and including oppositely d isposed delecting elements positioned within the resonator, the beam path lying between said deilecting. elements, said leads being connected to said cathode, collector and beam forming and deflecting electrode assembly, and a coaxial line coupling loop communicating with said resonator andrextending through and sealed through said header.

GEORGE ROSS KILGORE.

WARREN R. FERRIS.

CARL SHULMAN. 

